1. Field of the Invention
The present invention relates to a cartridge for a mixer faucet and a mixer faucet fitted with such a cartridge, and a thermostatic assembly for regulating a stream of fluid.
2. Brief Description of the Related Art
The invention relates more particularly to the faucet cartridges supplied with two fluids having different respective temperatures, designed to be mixed inside the cartridge by means of at least two ceramic disks that can be moved relative to one another. To modify the relative configuration of these disks, and thereby control the temperature and the flow of the mixture, the cartridges are usually fitted with a single operating member, consisting, in practice, of a lever more or less inclined relative to the central longitudinal axis of the cartridge. This lever is designed to be operated by the user of the faucet so that, usually, a rotation of the lever about the longitudinal axis of the cartridge modifies the temperature of the mixed fluid while a tilting of the lever, while remaining in the same vertical plane, modifies the flow of the mixture. A composition of these two movements makes it possible to modify both the temperature and the flow. Thus, the proportion of the two mixed fluids may vary from 100%-0% to 0%-100%, which means that the temperature of the mixture may vary from “all cold” to “all hot”.
Such faucets are routinely used in the installations for delivering domestic water, in which the hot water is delivered at a temperature that can reach 80° C. approximately, so that the risks of scalding are real.
For the purpose of remedying this disadvantage, it has been proposed to provide a stop to block the rotation of the lever before the cold water inlet duct is completely closed off, which makes it possible to limit the temperature of the mixed water on the “hot” side. However, the positioning of this stop depends on the pressure and temperature conditions of the cold water and of the hot water supplying the cartridge. Consequently, when, for example, the cold water pressure falls or the hot water temperature increases, the temperature of the mixed water increases by several degrees and thereby reaches a level at which the risk of scalding subsists. In addition, in the case of a total cut-off of cold water supply, the water coming out of the cartridge has a temperature equal to that of the hot water coming in, which is particularly dangerous.
Thermostatic cartridges with a single regulating lever are furthermore known, for example from WO-A-96/26475. They are costly and have a large space requirement which renders them, in practice, unusable in standard size mixer faucets that are usually designed to receive a cartridge of 40 mm in diameter.
Another example of a thermostatic cartridge is provided by EP-A-1 048 997. This cartridge includes a bypass duct directly connecting a cold water inlet to a mixed water outlet, the closing of this duct being controlled by a thermostatic element whose heat-sensitive portion is swept over by the flow of mixed water. If the temperature of the mixed water is too high, the cold water is directly admitted at the outlet of the cartridge via the bypass duct. However, in the case of an insufficient supply of cold water, and even in the case of total cut-off, the risks of scalding persist. In addition, the space requirement of the arrangements relating to the bypass duct makes them difficult to install in standard size cartridges.
In another field, namely that of conventional valves, that is to say whose faucet body is not designed to receive interchangeable cartridges, particularly cartridges with ceramic disks, FR-A-2 424 459 proposes a mixer faucet whose body incorporates a thermostatic element whose heat-sensitive portion is swept over by the flow of mixed water coming out of the faucet, while its piston operates a valve element for closing off the flow of hot water entering the faucet. The hot water inlet channel is furnished for this purpose with a sealing ring against which the valve element presses in its direction of translation by the piston when the temperature of the mixed water reaches a predetermined value. If this temperature is exceeded, the valve element presses on the ring and moves it in translation along the channel, compressing a dedicated spring inserted between the ring and a wall of the faucet body. This spring makes it possible to push the ring back to its initial position along the hot water channel when the temperature of the mixed water reduces. This spring, which therefore serves as an overtravel spring for the thermostatic element and which is indispensable to the correct operation of the faucet, occupies a significant space within the faucet body and substantially increases its space requirement in the longitudinal direction of the thermostatic element. The faucet body consequently has a longitudinal dimension much greater than that of standard faucets and hence very much greater than the diameter of the interchangeable cartridges capable of being fitted into such standard faucets.